Try to fix Snap.

Thanks to xet7 !

Related #4524,
related #4423

snapcraft.yaml

@@ -1,5 +1,6 @@
 name: wekan
 version: '6.26'
+base: core20
 summary: Open Source kanban
 description: |
    WeKan ® is an Open Source and collaborative kanban board application.
@@ -64,9 +65,12 @@ apps:
 
 parts:
     mongodb:
-        source: https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu1604-3.2.22.tgz
+        source: https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-ubuntu2004-5.0.8.tgz
         plugin: dump
-        stage-packages: [libssl1.0.0]
+        stage-packages:
+            - libssl1.1
+            - libcurl3-dev
+            - libcurl4-openssl-dev
         filesets:
             mongo:
                 - usr
@@ -79,18 +83,18 @@ parts:
 
     wekan:
         source: .
-        plugin: nodejs
-        node-engine: 14.19.3
-        node-packages:
-            - node-gyp
-            - node-pre-gyp
-            - fibers
+        plugin: npm
+        npm-node-version: 14.19.3
+        #npm-packages:
+        #    - node-gyp
+        #    - node-pre-gyp
+        #    - fibers
         build-packages:
             - build-essential
             - ca-certificates
             - apt-utils
-            - python
-#            - python3
+#            - python
+            - python3
             - g++
             - capnproto
             - curl